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EPA mileage not matching energy screen

Swoosh99

Member
May 13, 2021
19
4
Hawaii
I have a MY standard range and the EPA states that I should get 244 mi @ 260wH/mi.
However, when I check my energy graph screen, it shows that the rated wH/mi line is about 220wH/mi.

Normally, a lower 220wH/mi would mean that the car is more efficient. However, in this case it's bad for me because I'm averaging 260wH/mi. I need to get my wH/mi down to a lower 220wH/mi to be able to reach 244mi rated EPA miles.

My question is, why would the rated wH/mi show a lower value than what the EPA stated?
Does your EPA wH/mi match the rated line on the rebel graph?
My battery did degrade a little to 241 mi from 244 mi. But that doesn't account for the major discrepancy.

Thanks
 

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ATPMSD

Member
Mar 12, 2021
262
256
Atlanta, GA
The EPA sticker is a bit complicated.

129 eMPG figure is based on how far the car will go on 33.7 kWh. Why 33.7? According to the EPA, burning one gallon of gas produces 115,000 BTUs (British thermal units). To generate the same amount of heat by way of electricity, it takes 33.7 kilowatt-hours (kWh). Kilowatt-hours is the standard energy unit for electricity.

The 26 kWh is how much energy it takes for the car to travel 100 miles.

And then there is the range figure. The above two values are bases on “wall to wheels” and take into account power lost when charging. The range is a “battery to wheels” calculation and assumes a fully charged battery.

Your mileage will definitely vary based on how you drive your car - just as it does with ICE cars. Think about an ICE car with say an MPG of 30 and now assume you get 27 MPG based on your driving style. That equates to 10% less. If your EV has an eMPG of 129, that 10% translates to 12.9 miles. Bigger number but the same relative amount.
 
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TomServo

Active Member
Apr 10, 2014
1,529
988
Belleville IL
Another fact to consider when comparing your results to decades of driving ICE vehicles, is backwards. With ICE vehicles they get BETTER fuel mileage at FREEWAY speeds and WORSE fuel mileage at CITY speeds. It’s the opposite with EV’s.
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
Another fact to consider when comparing your results to decades of driving ICE vehicles, is backwards. With ICE vehicles they get BETTER fuel mileage at FREEWAY speeds and WORSE fuel mileage at CITY speeds. It’s the opposite with EV’s.
The ironic thing is that I am getting way worse mileage on the city than on the highway with my MY. With the summer heat and the stop and go traffic, I average 350wH/mi in the city and 220wH/mi on the highway. Disappointing because my driver's are mostly city.
 
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Fourdoor

Member
May 31, 2016
860
686
North East Arkansas
I have a MY standard range and the EPA states that I should get 244 mi @ 260wH/mi.
However, when I check my energy graph screen, it shows that the rated wH/mi line is about 220wH/mi.

Normally, a lower 220wH/mi would mean that the car is more efficient. However, in this case it's bad for me because I'm averaging 260wH/mi. I need to get my wH/mi down to a lower 220wH/mi to be able to reach 244mi rated EPA miles.

My question is, why would the rated wH/mi show a lower value than what the EPA stated?
Does your EPA wH/mi match the rated line on the rebel graph?
My battery did degrade a little to 241 mi from 244 mi. But that doesn't account for the major discrepancy.

Thanks

Looking at the photo you posted, you are getting 223 wh/mile on average, so your real world range in the driving you have been doing (more efficient than EPA test) is significantly more than 244 miles. If you keep driving like you have been driving you should get over 280 miles of range. What is the "rated line" you are talking about? I only see your average line and the non-averaged instantaneous usage line.

Keith
 
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NickFie

Member
Sep 28, 2017
548
621
Near Philadelphia, PA
EVs convert electricity into forward motion so efficiently that auxiliary power drains are far more visible. Heating and air conditioning are the most significant.

Unless you are willing to turn off air conditioning, roll down the windows and bake at ambient temperature, there’s not much you can do. If it’s any comfort, Tesla is more energy-efficient in stop and go traffic than most vehicles.

The first summer after we bought our 2017 Model S, we were trapped for several hours in a highway backup caused by a horrific accident. My wife lost her range anxiety when we observed that charge level dropped only about 1% per hour with air conditioning, cabin lights and outside lights.
Our KWh/mile for that period was astronomical, yet we consumed far less energy than any other vehicle around us.
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
EVs convert electricity into forward motion so efficiently that auxiliary power drains are far more visible. Heating and air conditioning are the most significant.

Unless you are willing to turn off air conditioning, roll down the windows and bake at ambient temperature, there’s not much you can do. If it’s any comfort, Tesla is more energy-efficient in stop and go traffic than most vehicles.

The first summer after we bought our 2017 Model S, we were trapped for several hours in a highway backup caused by a horrific accident. My wife lost her range anxiety when we observed that charge level dropped only about 1% per hour with air conditioning, cabin lights and outside lights.
Our KWh/mile for that period was astronomical, yet we consumed far less energy than any other vehicle arou
Looking at the photo you posted, you are getting 223 wh/mile on average, so your real world range in the driving you have been doing (more efficient than EPA test) is significantly more than 244 miles. If you keep driving like you have been driving you should get over 280 miles of range. What is the "rated line" you are talking about? I only see your average line and the non-averaged instantaneous usage line.

Keith
Unfortunately, in order to get that 223 wH/mi, I had to go downhill. My concern is that the rated EPA line is also showing around 223wH/mi (nearly overlapping grey line). But based on EPA sticker, the rated grey line should be closer to 260wH/mi not 220wH/mi. So this means, I need to be driving near 220wH/mi efficiency to obtain the rated 244mi by the EPA and not the 260wH/mi as they claimed.
 
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Fourdoor

Member
May 31, 2016
860
686
North East Arkansas
Unfortunately, in order to get that 223 wH/mi, I had to go downhill. My concern is that the rated EPA line is also showing around 223wH/mi (nearly overlapping grey line). But based on EPA sticker, the rated grey line should be closer to 260wH/mi not 220wH/mi. So this means, I need to be driving near 220wH/mi efficiency to obtain the rated 244mi by the EPA and not the 260wH/mi as they claimed.
Ahhh, missed the grey line.

Looking at that EPA sticker, you are rated at 140 mpge city (240.8 wh/mile, or 4.2 miles/kwh) and 119 highway (283.2 wh/mile, or 3.5 miles/kwh) and also rated at 26 kWh / 100 miles (260 wh/mile, or 130 mpge or 3.9 miles/kwh)

Why in the hell are they mixing units giving stats in both mpge (a useless unit) and KW per 100 miles? I guess the 26 kWh per 100 miles is the same as the 129 mpge of the "combined" EPA rating.

Anyway, I think the grey line on that screen takes into account your current driving style (in your case, over the last 5 miles), not the EPA ratings. People with more Tesla specific experiance can give you better info... I haven't finished reading the manual yet :)

Keith
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
Ahhh, missed the grey line.

Looking at that EPA sticker, you are rated at 140 mpge city (240.8 wh/mile, or 4.2 miles/kwh) and 119 highway (283.2 wh/mile, or 3.5 miles/kwh) and also rated at 26 kWh / 100 miles (260 wh/mile, or 130 mpge or 3.9 miles/kwh)

Why in the hell are they mixing units giving stats in both mpge (a useless unit) and KW per 100 miles? I guess the 26 kWh per 100 miles is the same as the 129 mpge of the "combined" EPA rating.

Anyway, I think the grey line on that screen takes into account your current driving style (in your case, over the last 5 miles), not the EPA ratings. People with more Tesla specific experiance can give you better info... I haven't finished reading the manual yet :)

Keith
The dashed line is based on my driving style and the solid grey line should be the rated EPA wH/mi. Wondering does the solid grey line match what is shown in your EPA sticker?
 
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srlawren

Member
Aug 3, 2020
987
653
Vancouver, BC, Canada, Eh?
I have a MY standard range and the EPA states that I should get 244 mi @ 260wH/mi.

@Swoosh99 just a small note: that's not what they're stating. This is not an expectation of what you should get, but a number you can compare against other vehicles. There are far too many variables that determine the actual range/consumption rate you personally will get. The same is true for ICE vehicles, few ever get their EPA mpg rate in real-world driving either.
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
@Swoosh99 just a small note: that's not what they're stating. This is not an expectation of what you should get, but a number you can compare against other vehicles. There are far too many variables that determine the actual range/consumption rate you personally will get. The same is true for ICE vehicles, few ever get their EPA mpg rate in real-world driving either.
I disagree, the EPA range number should be achievable if you are able to drive at their specified efficiency,wH/mi. I understand that there are millions of variables that can affect efficiency, but if we managed to get to EPAs stated level of efficiency then we should get its stated range.

My goal is to understand if I drive and achieve a target wH/mi, then I should get near the EPA stated range.
But right now, my target wH/mi isn't matching with EPAs wH/mi.
 
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srlawren

Member
Aug 3, 2020
987
653
Vancouver, BC, Canada, Eh?
I disagree, the EPA range number should be achievable if you are able to drive at their specified efficiency,wH/mi. I understand that there are millions of variables that can affect efficiency, but if we managed to get to EPAs stated level of efficiency then we should get its stated range.

My goal is to understand if I drive and achieve a target wH/mi, then I should get near the EPA stated range.
But right now, my target wH/mi isn't matching with EPAs wH/mi.

@Swoosh99 I think we're saying the same thing here: your wH/mi is almost never going to be exactly what the EPA states, at least not for any length of time. This is exactly the same as your mpg in an ICE vehicle almost never matches the EPA number on the sticker. The EPA test (or has the manufacturer test) under specific conditions. Based on seeing lots of discussions here, it seems you can get around their number in your MY by driving around 50-55 mph on a level surface in ideal temperatures and no headwindws or rain, likely without any climate control active, etc. If your goal is to get what they're saying you can possibly get under certain conditions (not should get), then that's approximately what you're looking for.
 
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AlexHung

Member
Mar 13, 2021
300
281
Santa Cruz, CA
@Swoosh99 I think we're saying the same thing here: your wH/mi is almost never going to be exactly what the EPA states, at least not for any length of time. This is exactly the same as your mpg in an ICE vehicle almost never matches the EPA number on the sticker. The EPA test (or has the manufacturer test) under specific conditions. Based on seeing lots of discussions here, it seems you can get around their number in your MY by driving around 50-55 mph on a level surface in ideal temperatures and no headwindws or rain, likely without any climate control active, etc. If your goal is to get what they're saying you can possibly get under certain conditions (not should get), then that's approximately what you're looking for.
In another word, get yourself a test track. Replicate EPA test protocol and then we can chat! LOL
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
@Swoosh99 I think we're saying the same thing here: your wH/mi is almost never going to be exactly what the EPA states, at least not for any length of time. This is exactly the same as your mpg in an ICE vehicle almost never matches the EPA number on the sticker. The EPA test (or has the manufacturer test) under specific conditions. Based on seeing lots of discussions here, it seems you can get around their number in your MY by driving around 50-55 mph on a level surface in ideal temperatures and no headwindws or rain, likely without any climate control active, etc. If your goal is to get what they're saying you can possibly get under certain conditions (not should get), then that's approximately what you're looking for.
I think there's a misunderstanding. I know that if I drive typically, I won't get EPA's stated wH/mi nor EPA's range because those are based on ideal conditions. BUT, if I managed to drive in ideal conditions (downhill, no AC, no load, etc.) AND achieved EPA's wH/mi then I should also achieve EPA's stated range. This is the part that I am concerned about, I am achieving EPA's wH/mi but not EPA's range.

For example, EPA's stated wH/mi is 260wH/mi and the range is 244 and the battery size is 63KWH.
The math for this works out perfectly, 260wH/mi X 244mi = 63KWH.

My concern is that the EPA's window sticker shows 260wH/mi, but my energy graph's EPA rated solid grey line shows 220wH/mi. This is a huge discrepancy from the EPA window sticker and affects my expected range. Now, I have to drive better than 220wH/mi to achieve 244 mi versus driving better than the expected 260wH/mi.
 
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ATPMSD

Member
Mar 12, 2021
262
256
Atlanta, GA
Not sure if this also factors into your analysis, but one thing you may have failed to consider is Vampire drain. When you are not driving you are still consuming up to 250 watts per hour, and perhaps even more if overheat protection kicks in. You can get this down to about 50 watts per hour if you turn off Sentry, Summons, and overheat protection. Assuming you do not charge, note the mileage when you exit the car and when you return.
 
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Swoosh99

Member
May 13, 2021
19
4
Hawaii
Not sure if this also factors into your analysis, but one thing you may have failed to consider is Vampire drain. When you are not driving you are still consuming up to 250 watts per hour, and perhaps even more if overheat protection kicks in. You can get this down to about 50 watts per hour if you turn off Sentry, Summons, and overheat protection. Assuming you do not charge, note the mileage when you exit the car and when you return.
Thanks I have factored those in, but my concern is not on how to become more efficient, but rather why my car's reported rated EPA wH/mi does not match what's on the EPA sticker. Do you still have your EPA sticker and could you confirm if the wH/mi matches the solid grey line in your energy chart? My EPA sticker shows 260 wH/mi and the solid grey line shows 220 wH/mi, these two values should be identical. Thanks.
 
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ATPMSD

Member
Mar 12, 2021
262
256
Atlanta, GA
I do not see a 260 wH/mi figure on the posted EPA sticker. As to the solid grey line you take your car battery size and divide by the EPA range. In my case my battery is 100 kWh and my range is 402, that equal 248 wH / mi which is my grey line on the graph.
 
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